Variable speed gear transmission



Aug. l, 1939. s. c. GEBx-:RT 2,167,748

VARIABLE SPEED GEAR TRANSMISSION Filed Nov. 29, 1937 4 Sheets-Sheet 1 gli yl//la E g 5 7 4 f 75 n m i z 74 m v l 63 H 70 Il Z'A/ Vf/V To@ (67 SEVER C. @55E/e7- Aug. 1, 1939., s. c. GEBERT VARIABLE SPEED GEAR TRANSMISSION Filed Nov. 29,

1957 4 Sheets-Sheet 2 Mg' L R39.,

s. c. GEBEN-r I7,748

VARIABLE SPEED GEAR TRANSMISSION Filed Nov. 29, 1937 l Sheets-Sheet 3 Aug. l, 1939. s. c. GEBERT VARIABLE SPEED GEAR TRANSMISSION Filed Nov. 29, 1937 4 Sheetssheet 4 4 ZA/vf /v Toe SEI/EA C. G11-"BERT,

i7 TOP/VE Y Patented Aug. 1, 1939 PATENT OFFICE VARIABLE SPEED GEAR TRANSMISSION Sever C. Gebert, Chicago, Ill., assignor to Fairbanks, Morse & Co., Chicago, Ill., a corporation of Illinois Application November 29, 1937, Serial No. 176,985

Claims.

'Ihis invention relates to an improved power unit especially adapted for driving the fuel feed screw of a mechanical stoker, and more particularly to an improved gear transmission, opera 5 tively interconnected between a power device and the Stoker feed Screw, for enabling the feed screw to be driven at any of a number of predetermined rates of Speed.

An object of my invention is to provide a highly compact transmission unit of this character, so constructed that speed changes may be readily and quickly accomplished by a simple adjustment of a single control element.

Other objects and advantages will appear from l5v the following description and accompanying drawings wherein Fig. 1 is a side elevation of the device Showing the same in connection with a Stoker and furnace, the latter being shown in section; Fig. 2 is an end view of the transmission unit and its driving means, with parts broken away and in Section; Fig. 3 is a longitudinal section taken at the line 3-3 of Fig. 2; Fig. 4 is a section taken at the line 4-4 of Fig. 3; Fig. 5 is a sectional View taken at line 5v5 of Fig. 2;

Figs, 6 and 7 are fragmentary views showing the transmission gear cage in intermediate speed, and low speed feeding positions respectively, and Fig. 8 is a section taken on the line 8--8 of Fig. 4.

Referring to the drawings in detail, an application of my improved transmission assembly to a conventional mechanical Stoker is illustrated in Fig. 1, wherein I represents a furnace or other heating device, 2 the re pot thereof, 3 an underfeed fuel duct or conduit, and 4 a fuel hopper which connects at its -bottom with the fuel duct so as to provide a relatively constant Supply of fuel thereto. Extending longitudinally through the duct 3 is a screw conveyor 5 having a central shaft 6 which is provided at its outer end with an enlargement I in which is formed an angular recess 8. This recess may be either square as shown, or of any other non-circular shape to receive a correspondingly Shaped end 9 of the transmission drive shaft Il).

'I'he transmission consists of a casing l I having a removable end plate I3 which is secured in place by bolts I4, a gasket I5 being compressed between the mating surfaces of the casing and end plate to form a liquid tight junction. The

'U opposite end wall i6 of the casing is provided with an outwardly projecting circular boss Il which is bored to receive a thrust bearing I8 that journals one end of the drive shaft IIl, ancl a washer assembly i9 which protects the bearing 55 I 3 against coal dust and prevents the escape of that the gears 45 and 46 rotate together.

lubricant from the transmission casing. The opposite end of drive shaft I0 is journalled and supported by end plate I3 in a manner hereinafter explained. Mounted on the Shaft I0 within the casing is a sleeve 20 which may be bushed 5 as at 2I with bearing metal of any suitable type, and formed integrally with this sleeve is .t driving gear 22. A worm wheel 23 is secured on the sleeve 20 by means of keys 24 as shown, or may be otherwise secured on the sleeve, the essential 10 feature being that the worm wheel 23, sleeve 20 and gear 22 operate as a unit. Mounted on shaft I0 for rotating relative thereto is an integral gear cluster composed of the gears 25. 26 and 21, such gear cluster being disposed adjacent l5 to the gear 22. It should be understood that gear 22 and the cluster 25-26-21 are rotatable on shaft I0 relative to each other and to the said shaft.

Loosely mounted on the shaft Il) is a gear 29 20 having anaxially projecting hub 3l] which extends through a bearing bushing 3| carried by a boss 32 formed on the plate I3. The hub 30 is provided with a pore 33 into which a portion of a shear pin 34 extends, the remainder of such pin 25 extending into a bore 35 formed in the collar 36, which collar is provided with an angular bore 3'I to accommodate the correspondingly shaped end 38 of the shaft I0. By means of the collar 3B and shear pin, the gear 29 and shaft l0 are 30 locked together for joint rotation. The collar 36 is held against longitudinal displacement on the angular portion of the shaft by a set screw 39. A removable cap 40, threaded to the end of the bushing 3|, encloses the members on the end 35 of shaft I0 and prevents oil leakage from the interior of the transmission case.

Formed on the interior of the Wall I6 is a bracket 4I in which is journalled a trunnion 42 which projects from one end of the cam or eccen- 40 tric 43. Projecting from the opposite end of the cam 43 is a shaft 44 which is in axial alignment with the trunnion 42 and which Serves as a counter shaft for gears 45 and 46 which are provided with a bearing bushing 41 and rotate freely '45 on the counter shaft 44. These gears maywbe integrally united as shown, or/they may be made separate and secure together, it being essential The counter shaft 44 is provided with a reduced ex- 50 tension 48 which projects through and is journalled in the end plate I3. On the end of the shaft 48 is mounted a crank 49 which terminates at its free end in a cylindrical projection 50 provided with a bore 5I in which a coil spring 52 is located. A plunger 53 is slidably mounted in the borea 5I and is normally urged toward the end plate I3 by the coil spring 52. The plunger is provided with a stem or shaft 54 which projects centrally through the coil spring 52 and through the closed end 55 oi' the cylindrical projection 53. The s m or shaft 54 has its free end secured to the cl ed end 53 of a sleeve 51 which slidably mounted on the cylindrical projection 3 and serves as a handle for effecting angular adjustment of cam 43.l Plunger 53 is normally urged by the spring in an extended position for engagement with end plate I3 at any of a series of recesses 33 formed therein, and is adapted to be disengaged from the end plate by endwise manipulation of sleeve 51.

Located on the outer face of the endplate I3 (Fig. 2), are lands 53, 59, 33, 3| and 52. These lands are evenly spaced clrcumferentially about the shaft end 43 and located in the path of travel of the plunger 53. Each of the lands is provided with a bore 33 in which the plunger 53 can enter and thus lock the crank against accidental displacement. The lands 59, 53 and 9| have their opposite ends beveled so that the plunger 53 can ride up onto the same regardless of the direction of crank travel. Each of the lands 53 and 32 is beveled at on end and provided at the opposite end with an outstanding shoulder or stop, indicated at 34 and 35, these stops serving to limit the extent of angular movement of the crank.

Introduction of lubricant into the casing is made through a ller neck 33 extending from the end plate I3, and a drain opening having a threaded plug 51, also in the end plate I3, so as to enable withdrawal of the lubricant whenever desird.

, The gear'caseis provided with an arcuate projectlon 33 (Fig. 5), forming a worm housing and in the ends of the housing are located thrust bearings 69 and 13 in which the worm shaft 1I is rotatably mounted.. The worm flight 12 of shaft 1I drives the worm wheel 23. That end of the worm shaft which is journalled in the bearing 39 projects outwardly beyond the end of the worm housing-and carries a pulley 13. A belt 14 operatively connects pulley 13 to pulley 15 on the shaft of the driving motor 13, the motor being mounted on a plate 11 carried by the transmission case.

Located within the transmission case and encircling gear 22 and gear cluster 25-25-21 is a cage structure 'or gear cage composed of spaced side plates` 13 and 19. These plates are connected together at'one end by a sleeve 33 in which the cam or eccentric 43 is journalled, and at the opposite end by a web or bridge piece 3l. 'I he side plates 13 and 19 are provided with aligned central openings 32 through which the shaft I3 passes, these openings being of such size that the idler frame can be freely moved by the cam 43 without contacting or interfering with any of the gears mounted on the shaft I3. The plate 13 is provided with an inward jog or bend as indicated bythe numeral 33, so that the frame or cage is narrower at its cam end than at its web end. The gear 21 of the cluster, projects outwardly beyond one side of plate 13 and is in mesh with the countershaft gear 45 at all times. The bridge piece 3| is provided with an opening 34 which loosely receives a pin 35 projecting internally from the casing side wall. This pin is constituted by an axial extension of a bolt 33 threaded through the casing side wall 1and serves to support the web end of the cage, the opposite end of the cage being supported by the cam 43.

The plates 13 and 13 have secured therein in any well known manner, the ends of shafts 31, 3l and 89. These shafts extend across the space between the plates and have compound gears rotatably mounted thereon. The shaft 31 carries the integral gears 93 and 3|; the shaft '33 carries integral gears 32 and 93, and the shaft 39 carries integral gears 94 and 95. The members 33, 32 and 94 of the compound cage gears are all of the same size and are disposed in the plane of gear 22 sol that any one thereof, selectively, can be meshed with the gear 22, effected by lateral shifting movement of the cage. The gear 9| is axially spaced from its companion gear 93 and lies in the plane of gear 21 of the cluster; the gear 93 lies in the plane of gear 23 of the cluster and gear 95 lies in the plane of gear 25. The cage gears are circumfercntially spaced around the frame structure which supports the same, the angular space between each set of cage gears being approximately degrees. It will now appear that rotation of the cam or eccentric 43 by means of -crank 49 imparts a pivotal or swinging motion to the cam end of the gear cage, the opposite end of the vgear cage pivoting on the pin 35 which lits the opening in the bridge piece 3l with sumcient play to permit of the aforesaid lateral swinging movement. Continued turning of the eccentric causes the gear cage to be shifted bodily so that its bridge piece 3l travels along pin 35. 'I'hus the described mounting provides for both pivotal and reciprocating movement of the gear cage, the off-center position of the gear cage with respect to the axis of shaft I3 being adjustable by means of crank 49. The cage gears are so dimensioned, and their locations on the cage frame so arranged with regard to the throw of eccentric 43 that only one set thereof is capable of being lenmeshed with the gears on shaft I3 at a particular time. In certain so-called intermediate portions of the eccentric, none of the cage gears operatively engage the shaft gears, which, of

course, produces a gap in the driving sequence.

From the foregoing description it will appear that the worm wheel 23 is operatively connected at all times with motorm13, and is adapted to be driven by the motor at a relatively reduced speed. through the pulleys 13 and 15, belt 14 and worm shaft 1I. Worm wheel 23 is directly connected to gear 22 by sleeve 23 which is loosely disposed on the main drive shaft I3. In axial adjacence with gear 22 on shaft I3 is the integral gear cluster composed of gears 25, 25 and 21, such gear cluster being loose on shaft I3 for rotation relative to the shaft and to the gear 22. The and gear 21 of the cluster is enmeshed at all times with gear 45,

joumalled on countershaft 44, the gear 21 serving I to drive gear 29loosely disposed on main shaft I3, through gear 43. Gear 29 is operatively connected to shaft I3 through shear pin 34 and collar 33. In the explanation thus far, no mention has been made of the means by which rotation of gear 22 is imparted to the gear cluster adjacent thereto. Such means are found in the laterally shiftable cage structure with its associated sets of compound gears which, selectively, link gear 22 and the gear cluster. Such means enable the gear cluster, and hence the conveyor feed screw, to be driven at a number of different rates of speed and the construction, assembly and mounting arrangement thereof constitute a highly important part of the present invention.

As illustrated in Fig. 4 and heretofore described, the gear carriage or frame, characterized by the side plates 'i3 and ld, encircles the shaft it and is adapted to be shifted in a plane at right angles to said shaft by means oi the ec centric or cam d3. Adjustment oi cam 43 is urider the control of crank 49, and when the latter is temporarily locked by its plunger '53 in the position indicated in Fig. 7, operative connection between gear 22 and gear 2l of the cluster is eiected through the compound gear @A2- td mounted on the carriage. Due to the relative proportions of the component gears of recited train, a lslow speed condition oi the conveyor worm shaft results. if an intermediate speed condition of the worm shaft is desired, crank dd i is moved and locked at position designated i on i integrally united` gears on said shaft, a train of gears operatively connecting said gear cluster y the end plate it (Fig. 2) which causes disengagement of compound gear 92--93 with gears 22 and il and engagement oi compound gear 941-95 with gears 22 and it. A further adjustment of crank di may be edected to shift the gear frame and replace the intermediate speed gear 9L-95 with high speed gear til- 9i in the described train. Two neutral or "ofP positions of the crank il@ are provided for, and when the crank is disposed in either of such positions, all three of the designated compound speed change gears are disengaged from gear 22 and thel integral gear clutch tib-ZS-ZTL which, of course, interrupts the continuity of the gear train and no power is transmitted to the screw conveyor.

Having fully described my invention, what ll claim and desire to secure by Letters Patent is:

i. A variable-speed transmission including a casing, a shaft journalledin said casing, a driving gear loosely disposed on said shaft, a cluster of and shaft, a cage structure encircling said shaft. a plurality of dual compound gears carried by the cage structure, each of said compound gears having one of its members disposed in the plane of said driving gear and its other member disposed in the plane of one of the gears of said cluster, means on the casing supporting one side of said cage structure for pivotal and reciprocating movement, an eccentric mounted in the casing at the opposite side of the cage structure, adapted to impart pivotal and reciprocating movement thereto 'whereby to place any selected one oi the cage gears into operative engagement with said prising a pair of axially spaced annular discs dii and a plurality of compound, intermediate gears spaced circumierentially around and disposed between the discs, means on the casing at one side l imparting movement as aforesaid to the gear cage whereby to enmesh any selected intermediate to the axis oi the driving and driven gears, a

control shaft having an eccentric thereon iournalled in a peripheral portion of the gear cage opposite to said bridge piece, said eccentric being adapted to impart the aforesaid movement to the gear cage whereby to place any selected one of the compound gears into operative engagement with the driving and driven gears.

i. In a variable speed transmission, a casing, a main shaft therein, a driving gear and a coinpound driven gear loosely mounted on said shaft,

Aa gear train operatively interconnecting said driven gear and shaft, a gear cage encircling the driving and driven gears, comprising axially spaced annular-discs, an apertured bridge member and a sleeve disposedl on relatively opposite sides of the cage structure, connecting the discs together, a plurality oi circumierentially spaced compound gears carried by and disposed between said discs, said intermediate gears being adapted, selectively, to interconnect the driving and driven gears, apin projecting from the casing through the aperture in said bridge member, said pin serving to support one side of the gear cage ior reciprocating and pivotal movement in a plane transverse to the main shaft; a cam rotatable in said sleeve for moving the gear cage, whereby to place any selected intermediate gear in operative engagement with the driving and driven gears.

5. A variable speed transmission including a casing, a main shaft and a countershait journalled therein, a irstv gear fixed .to the main shaft, a cluster gear loosely mounted on the main shaft, a compound gear loosely mounted on the countershaft and meshing with said iirst gear and cluster gear, said countershait having an eccentric ilormed thereon, a third gear coaxial with said cluster and rotatable relative thereto,

'an annular ire encircling said main shaft, a

sleeve for said eccentric iormed on onesideoi said trame, means on said casing engaging the opposite side of said frame, said means serving to support the trarne for reciprocating and pivotal movement as imparted to the trame by said eccentric, a plurality oi compound gears spaced `about and iournalled on said frame, said countershait serving as a means tor shitting the frame 'whereby any selected one oi the tre gears may be intermeshed with said cluster gear d im 

